Modificación de la salida de la cámara utilizando SurfaceTexture y OpenGL

Question

Estoy intentando filtrar la transmisión procedente del hardware de la cámara ejecutándola a través de un filtro openGL, y luego mostrándola en un GLSurfaceView. Cuando OpenGL va a hacer que el marco, el LogCat escupe repetidamente un error:

[unnamed-3314-0] updateTexImage: clearing GL error: 0x502

0x502 es un error de OpenGL genérico, y realmente no me ayuda a localizar el problema. Esta es una secuencia de cómo funciona el código (o al menos debería funcionar como se ve en mi cabeza), y he copiado mi código debajo de eso. Espero que alguien más pueda ver cuál es mi problema.

1. Create new MyGLSurfaceView. This internally creates the new MyGL20Renderer object as well. This MyGLSurfaceView is set as the content view.
2. Once the MyGLSurfaceView is done inflating/initializing, this completion event triggers the renderer to create a DirectVideo draw object, which compiles/links the shaders defined and adds them to an openGL program. It then creates a new openGL texture object, and then calls back to the MainActivity with the texture object ID.
3. When the MainActivity method is invoked from the renderer, it creates a new SurfaceTexture object using the openGL texture object passed. It then sets itself as the surface's onFrameListener. It then creates/opens the camera object, sets the created SurfaceTexture as the video stream's target, and starts the camera feed.
4. When a frame is available from the feed, the onFrameAvailable sends a render request to the renderer. This is picked up on the openGL thread, which calls the SurfaceTexture's updateTexImage(), which loads the frame memory into the openGL texture. It then calls the DirectVideo's draw object, and the openGL program sequence is run. If I comment out this .draw() line, the mentioned error above disappears, so it seems likely that the problem lies somewhere inside here, but I am not ruling it out being caused by an improperly linked/created texture.

MainActivity.java

public class MainActivity extends Activity implements SurfaceTexture.OnFrameAvailableListener 
{ 
    private Camera mCamera; 
    private MyGLSurfaceView glSurfaceView; 
    private SurfaceTexture surface; 
    MyGL20Renderer renderer; 

    @Override 
    public void onCreate(Bundle savedInstanceState) 
    { 
     super.onCreate(savedInstanceState); 

     glSurfaceView = new MyGLSurfaceView(this); 
     renderer = glSurfaceView.getRenderer(); 
     setContentView(glSurfaceView); 
    } 

    public void startCamera(int texture) 
    { 
     surface = new SurfaceTexture(texture); 
     surface.setOnFrameAvailableListener(this); 
     renderer.setSurface(surface); 

     mCamera = Camera.open(); 

     try 
     { 
      mCamera.setPreviewTexture(surface); 
      mCamera.startPreview(); 
     } 
     catch (IOException ioe) 
     { 
      Log.w("MainActivity","CAM LAUNCH FAILED"); 
     } 
    } 

    public void onFrameAvailable(SurfaceTexture surfaceTexture) 
    { 
     glSurfaceView.requestRender(); 
    } 

    @Override 
    public void onPause() 
    { 
     mCamera.stopPreview(); 
     mCamera.release(); 
     System.exit(0); 
    } 

MyGLSurfaceView.java

class MyGLSurfaceView extends GLSurfaceView 
{ 
    MyGL20Renderer renderer; 
    public MyGLSurfaceView(Context context) 
    { 
     super(context); 

     setEGLContextClientVersion(2); 

     renderer = new MyGL20Renderer((MainActivity)context); 
     setRenderer(renderer); 
     setRenderMode(GLSurfaceView.RENDERMODE_WHEN_DIRTY); 

    } 
    public MyGL20Renderer getRenderer() 
    { 
     return renderer; 
    } 
} 

MyGL20Renderer.java

public class MyGL20Renderer implements GLSurfaceView.Renderer 
{ 

    DirectVideo mDirectVideo; 
    int texture; 
    private SurfaceTexture surface; 
    MainActivity delegate; 

    public MyGL20Renderer(MainActivity _delegate) 
    { 
     delegate = _delegate; 
    } 

    public void onSurfaceCreated(GL10 unused, EGLConfig config) 
    { 
     mDirectVideo = new DirectVideo(texture); 
     texture = createTexture(); 
     GLES20.glClearColor(0.5f, 0.5f, 0.5f, 1.0f); 
     delegate.startCamera(texture); 
    } 

    public void onDrawFrame(GL10 unused) 
    { 
      float[] mtx = new float[16]; 
      GLES20.glClear(GLES20.GL_COLOR_BUFFER_BIT | GLES20.GL_DEPTH_BUFFER_BIT); 
      surface.updateTexImage(); 
      surface.getTransformMatrix(mtx); 

      mDirectVideo.draw(); 
    } 

    public void onSurfaceChanged(GL10 unused, int width, int height) 
    { 
     GLES20.glViewport(0, 0, width, height); 
    } 

    static public int loadShader(int type, String shaderCode) 
    { 
     int shader = GLES20.glCreateShader(type); 

     GLES20.glShaderSource(shader, shaderCode); 
     GLES20.glCompileShader(shader); 

     return shader; 
    } 

    static private int createTexture() 
    { 
     int[] texture = new int[1]; 

     GLES20.glGenTextures(1,texture, 0); 
     GLES20.glBindTexture(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, texture[0]); 
     GLES20.glTexParameterf(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, 
      GL10.GL_TEXTURE_MIN_FILTER,GL10.GL_LINEAR);   
     GLES20.glTexParameterf(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, 
      GL10.GL_TEXTURE_MAG_FILTER, GL10.GL_LINEAR); 
    GLES20.glTexParameteri(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, 
      GL10.GL_TEXTURE_WRAP_S, GL10.GL_CLAMP_TO_EDGE); 
    GLES20.glTexParameteri(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, 
      GL10.GL_TEXTURE_WRAP_T, GL10.GL_CLAMP_TO_EDGE); 

     return texture[0]; 
    } 

    public void setSurface(SurfaceTexture _surface) 
    { 
     surface = _surface; 
    } 
} 

DirectVideo.java

public class DirectVideo { 


    private final String vertexShaderCode = 
      "#extension GL_OES_EGL_image_external : require\n"+ 
      "attribute vec4 position;" + 
      "attribute vec4 inputTextureCoordinate;" + 
      "varying vec2 textureCoordinate;" + 
      "void main()" + 
      "{"+ 
       "gl_Position = position;"+ 
       "textureCoordinate = inputTextureCoordinate.xy;" + 
      "}"; 

     private final String fragmentShaderCode = 
      "#extension GL_OES_EGL_image_external : require\n"+ 
      "precision mediump float;" + 
      "uniform vec4 vColor;" + 
      "void main() {" + 
      " gl_FragColor = vColor;" + 
      "}"; 

     private FloatBuffer vertexBuffer, textureVerticesBuffer; 
     private ShortBuffer drawListBuffer; 
     private final int mProgram; 
      private int mPositionHandle; 
      private int mColorHandle; 
      private int mTextureCoordHandle; 


    // number of coordinates per vertex in this array 
    static final int COORDS_PER_VERTEX = 2; 
    static float squareVertices[] = { // in counterclockwise order: 
     -1.0f, 1.0f, 
     -1.0f, -1.0f, 
     1.0f, -1.0f, 
     1.0f, 1.0f 
    }; 

    private short drawOrder[] = { 0, 1, 2, 0, 2, 3 }; // order to draw vertices 

    static float textureVertices[] = { // in counterclockwise order: 
     1.0f, 1.0f, 
     1.0f, 0.0f, 
     0.0f, 1.0f, 
     0.0f, 0.0f 
    }; 

    private final int vertexStride = COORDS_PER_VERTEX * 4; // 4 bytes per vertex 

    private int texture; 

    public DirectVideo(int _texture) 
    { 
     texture = _texture; 

     ByteBuffer bb = ByteBuffer.allocateDirect(squareVertices.length * 4); 
     bb.order(ByteOrder.nativeOrder()); 
     vertexBuffer = bb.asFloatBuffer(); 
     vertexBuffer.put(squareVertices); 
     vertexBuffer.position(0); 

     ByteBuffer dlb = ByteBuffer.allocateDirect(drawOrder.length * 2); 
     dlb.order(ByteOrder.nativeOrder()); 
     drawListBuffer = dlb.asShortBuffer(); 
     drawListBuffer.put(drawOrder); 
     drawListBuffer.position(0); 

     ByteBuffer bb2 = ByteBuffer.allocateDirect(textureVertices.length * 4); 
     bb2.order(ByteOrder.nativeOrder()); 
     textureVerticesBuffer = bb2.asFloatBuffer(); 
     textureVerticesBuffer.put(textureVertices); 
     textureVerticesBuffer.position(0); 

     int vertexShader = MyGL20Renderer.loadShader(GLES20.GL_VERTEX_SHADER, vertexShaderCode); 
     int fragmentShader = MyGL20Renderer.loadShader(GLES20.GL_FRAGMENT_SHADER, fragmentShaderCode); 

     mProgram = GLES20.glCreateProgram();    // create empty OpenGL ES Program 
     GLES20.glAttachShader(mProgram, vertexShader); // add the vertex shader to program 
     GLES20.glAttachShader(mProgram, fragmentShader); // add the fragment shader to program 
     GLES20.glLinkProgram(mProgram);   
    } 

    public void draw() 
    { 
     GLES20.glUseProgram(mProgram); 

     GLES20.glActiveTexture(GLES20.GL_TEXTURE0); 
     GLES20.glBindTexture(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, texture); 

     mPositionHandle = GLES20.glGetAttribLocation(mProgram, "position"); 
     GLES20.glEnableVertexAttribArray(mPositionHandle); 
     GLES20.glVertexAttribPointer(mPositionHandle, COORDS_PER_VERTEX, GLES20.GL_FLOAT, false,vertexStride, vertexBuffer); 

     mTextureCoordHandle = GLES20.glGetAttribLocation(mProgram, "inputTextureCoordinate"); 
     GLES20.glEnableVertexAttribArray(mTextureCoordHandle); 
     GLES20.glVertexAttribPointer(mTextureCoordHandle, COORDS_PER_VERTEX, GLES20.GL_FLOAT, false,vertexStride, textureVerticesBuffer); 

     mColorHandle = GLES20.glGetUniformLocation(mProgram, "vColor"); 

     GLES20.glDrawElements(GLES20.GL_TRIANGLES, drawOrder.length, 
     GLES20.GL_UNSIGNED_SHORT, drawListBuffer); 

     // Disable vertex array 
     GLES20.glDisableVertexAttribArray(mPositionHandle); 
     GLES20.glDisableVertexAttribArray(mTextureCoordHandle); 
    } 
} 

Answer 1

mDirectVideo = new DirectVideo(texture); 
texture = createTexture(); 

debería ser

texture = createTexture(); 
mDirectVideo = new DirectVideo(texture); 

Shader

private final String vertexShaderCode = 
     "attribute vec4 position;" + 
     "attribute vec2 inputTextureCoordinate;" + 
     "varying vec2 textureCoordinate;" + 
     "void main()" + 
     "{"+ 
      "gl_Position = position;"+ 
      "textureCoordinate = inputTextureCoordinate;" + 
     "}"; 

    private final String fragmentShaderCode = 
     "#extension GL_OES_EGL_image_external : require\n"+ 
     "precision mediump float;" + 
     "varying vec2 textureCoordinate;       \n" + 
     "uniform samplerExternalOES s_texture;    \n" + 
     "void main() {" + 
     " gl_FragColor = texture2D(s_texture, textureCoordinate);\n" + 
     "}"; 

mColorHandle = GLES20.glGetUniformLocation(mProgram, "vColor");

debería ser

mColorHandle = GLES20.glGetAttribLocation(mProgram, "s_texture");

eliminar material de inicialización de DirectVideo draw.glVertexAttribPointer etc. Póngalo en alguna función init.

public void draw() 
{ 
    GLES20.glBindTexture(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, texture); 
    GLES20.glDrawElements(GLES20.GL_TRIANGLES, drawOrder.length, 
      GLES20.GL_UNSIGNED_SHORT, drawListBuffer); 
}